Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751943AbbHRAbp (ORCPT ); Mon, 17 Aug 2015 20:31:45 -0400 Received: from mail-pa0-f45.google.com ([209.85.220.45]:35489 "EHLO mail-pa0-f45.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750994AbbHRAbn (ORCPT ); Mon, 17 Aug 2015 20:31:43 -0400 Date: Mon, 17 Aug 2015 17:31:41 -0700 (PDT) From: David Rientjes X-X-Sender: rientjes@chino.kir.corp.google.com To: Jiang Liu cc: Andrew Morton , Mel Gorman , Mike Galbraith , Peter Zijlstra , "Rafael J . Wysocki" , Tang Chen , Tejun Heo , Tony Luck , linux-mm@kvack.org, linux-hotplug@vger.kernel.org, linux-kernel@vger.kernel.org, x86@kernel.org Subject: Re: [Patch V3 2/9] kernel/profile.c: Replace cpu_to_mem() with cpu_to_node() In-Reply-To: <1439781546-7217-3-git-send-email-jiang.liu@linux.intel.com> Message-ID: References: <1439781546-7217-1-git-send-email-jiang.liu@linux.intel.com> <1439781546-7217-3-git-send-email-jiang.liu@linux.intel.com> User-Agent: Alpine 2.10 (DEB 1266 2009-07-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1466 Lines: 39 On Mon, 17 Aug 2015, Jiang Liu wrote: > Function profile_cpu_callback() allocates memory without specifying > __GFP_THISNODE flag, so replace cpu_to_mem() with cpu_to_node() > because cpu_to_mem() may cause suboptimal memory allocation if > there's no free memory on the node returned by cpu_to_mem(). > Why is cpu_to_node() better with regard to free memory and NUMA locality? > It's safe to use cpu_to_mem() because build_all_zonelists() also > builds suitable fallback zonelist for memoryless node. > Why reference that cpu_to_mem() is safe if you're changing away from it? > Signed-off-by: Jiang Liu > --- > kernel/profile.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/kernel/profile.c b/kernel/profile.c > index a7bcd28d6e9f..d14805bdcc4c 100644 > --- a/kernel/profile.c > +++ b/kernel/profile.c > @@ -336,7 +336,7 @@ static int profile_cpu_callback(struct notifier_block *info, > switch (action) { > case CPU_UP_PREPARE: > case CPU_UP_PREPARE_FROZEN: > - node = cpu_to_mem(cpu); > + node = cpu_to_node(cpu); > per_cpu(cpu_profile_flip, cpu) = 0; > if (!per_cpu(cpu_profile_hits, cpu)[1]) { > page = alloc_pages_exact_node(node, -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/